Medical devices and medical testing may be used to diagnose, identify, monitor or otherwise determine health related information. As one example, blood coagulation screening tests, such as Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Activated Clotting Time (ACT), fibrinogen content (FIB) and Thrombin Time (TT) may be performed by clinical laboratories, health practitioners, and the like. Each of these tests relates to a type of blood coagulation characteristic under a certain condition.
Clinicians may use these tests for various purposes, such as to monitor anticoagulant therapy, to screen for a single factor deficiency, to screen for multiple factor deficiencies and/or to screen for specific or non-specific inhibitors. As one example, unfractionated heparin therapy is widely used as a treatment for thromboembolic (obstructive blood clots) disorders. In some cases, heparin therapy, or the amount of heparin administered, is determined based on the result of the APTT or ACT tests. However, there are many pre-analytical and analytical variables that can affect the PT, APTT, ACT, FIB or TT measurements, often giving dramatically different measurements from one test device or laboratory to another. This can produce a variance in the amount of a drug (e.g., heparin) or other therapy administered to the patient, and may lead to less than optimal therapeutic results.